Quote: Originally Posted by whs
Did this drive come from a Windows system or from a Mac or Linux.
In all likelihood, this is the exact explanation for the problem.
Ironically there was an essentially identical other thread
discussed just yesterday, with exactly this explanation. The hard drive had been given by a friend (and contained graduation photos and videos) who was a Mac user.
The screenshot of DISKMGMT in that other thread showed no file system at all on the partition of that external hard drive. Not RAW, not FAT32 or NTFS, not OFFLINE. ONLINE but no recognizable file system.
More revealing as the "giant clue", there was an EFI Partition on the drive shown in that DISKMGMT screenshot.
I agree... sounds very much like a Mac-formatted external drive.